[Sheepdog] [PATCH 0/6] merge sheep and puppy into one sheepdog daemon, collie

[FUJITA Tomonori]

On Fri, 4 Dec 2009 12:32:58 +0000
Chris Webb <chris at arachsys.com> wrote:

> > I guess that it takes some time until BTRFS matures so we've been thinking
> > about other options. One is using Berkeley DB for a super object.
> 
> A random off-the-wall suggestion: I wonder if it would be possible to use a
> filesystem directory tree to store the catalogue information instead of a
> single large database file or the current large block file. rename(2),
> link(2) and even symlink(2) are atomic on all POSIX filesystems, and are
> presumably optimised to be reasonably fast (?).

I think that it could be an option. We store vdi names in a super
object linearly (as old file systems (ext3, etc) do with
directories). It's not scale about the number of vdi. So we planed to
use more decent algorithm such as btree for that. Storing each vdi as
small file and put them into directories would solve both.

One drawback of that approach is that we add something that is not
an object (file). We need a new different recovery code, etc.